@Test
  public void forGraph_breadthFirst_tree() throws Exception {
    Traverser<Character> traverser = Traverser.forGraph(TREE);

    assertEqualCharNodes(traverser.breadthFirst('h'), "hdegabcf");
    assertEqualCharNodes(traverser.breadthFirst('d'), "dabc");
    assertEqualCharNodes(traverser.breadthFirst('a'), "a");
  }

  @Test
  public void forGraph_breadthFirstIterable_tree() throws Exception {

        if (result == 0) {
          return count(getElement());
        } else {
          return result;
        }
      }
    };
  }

  /** Returns the first node in the tree that is in range. */
  @CheckForNull
  private AvlNode<E> firstNode() {
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      return null;
    }
    AvlNode<E> node;

   */
  public void testCreateFromTreeMultimap() {
    Multimap<Double, Double> tree = TreeMultimap.create(KEY_COMPARATOR, VALUE_COMPARATOR);
    tree.put(1.0, 2.0);
    tree.put(2.0, 3.0);
    tree.put(3.0, 4.0);
    tree.put(4.0, 5.0);

    TreeMultimap<Double, Double> copyFromTree = TreeMultimap.create(tree);
    assertEquals(tree, copyFromTree);
    assertSame(Ordering.natural(), copyFromTree.keyComparator());

  public static <N> Traverser<N> forTree(SuccessorsFunction<N> tree) {
    if (tree instanceof BaseGraph) {
      checkArgument(((BaseGraph<?>) tree).isDirected(), "Undirected graphs can never be trees.");
    }
    if (tree instanceof Network) {
      checkArgument(((Network<?, ?>) tree).isDirected(), "Undirected networks can never be trees.");
    }
    return new Traverser<N>(tree) {
      @Override
      Traversal<N> newTraversal() {

   */
  public void testCreateFromTreeMultimap() {
    Multimap<Double, Double> tree = TreeMultimap.create(KEY_COMPARATOR, VALUE_COMPARATOR);
    tree.put(1.0, 2.0);
    tree.put(2.0, 3.0);
    tree.put(3.0, 4.0);
    tree.put(4.0, 5.0);

    TreeMultimap<Double, Double> copyFromTree = TreeMultimap.create(tree);
    assertEquals(tree, copyFromTree);
    assertSame(Ordering.natural(), copyFromTree.keyComparator());

   *       </ul>
   *   <li>another java.util.Set delegate implementation. In most modern JDKs, normal java.util hash
   *       collections intelligently fall back to a binary search tree if hash table collisions are
   *       detected. Rather than going to all the trouble of reimplementing this ourselves, we
   *       simply switch over to use the JDK implementation wholesale if probable hash flooding is

  /**
   * Returns a {@link Traverser} instance for the file and directory tree. The returned traverser
   * starts from a {@link File} and will return all files and directories it encounters.
   *
   * <p><b>Warning:</b> {@code File} provides no support for symbolic links, and as such there is no
   * way to ensure that a symbolic link to a directory is not followed when traversing the tree. In

    }

    /**
     * Recursively scan the given directory, adding resources for each file encountered. Symlinks
     * which have already been traversed in the current tree path will be skipped to eliminate
     * cycles; otherwise symlinks are traversed.
     *
     * @param directory the root of the directory to scan

                <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
                <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
                <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
                <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>

  @Test
  public void forGraph_breadthFirst_tree() throws Exception {
    Traverser<Character> traverser = Traverser.forGraph(TREE);

    assertEqualCharNodes(traverser.breadthFirst('h'), "hdegabcf");
    assertEqualCharNodes(traverser.breadthFirst('d'), "dabc");
    assertEqualCharNodes(traverser.breadthFirst('a'), "a");
  }

  @Test
  public void forGraph_breadthFirstIterable_tree() throws Exception {